Method and device for sound source positioning using microphone array

ABSTRACT

A method and device for sound source positioning using a microphone array. The method comprises: determining a horizontal axis that a microphone array rotates around as a reference axis; calculating, according to a sound emitted by a sound source that is collected by the microphone array, to obtain a first sound source estimated value indicating a sound source position in a three-dimensional space; acquiring an inclination angle between a plane in which the microphone array is located when it is rotating and a horizontal plane in which the reference axis is located; and according to the first sound source estimated value and the inclination angle, calculating out a second sound source estimated value on a horizontal plane corresponding to the first sound source estimated value, and using the second sound source estimated value as the determined sound source position.

TECHNICAL FIELD

The present disclosure relates to the technical field of acoustic signalprocessing, and particularly relates to a method and device for soundsource positioning using a microphone array.

BACKGROUND

With the progress of electronic information and acoustic technologies aswell as the development of smart hardware products such as robots, soundsource positioning techniques based on microphone arrays areincreasingly applied in smart products such as robots. A microphonearray is an array of a group of microphones located at differentpositions in the space and arranged according to a certain shape andrule, and is used for collecting and processing space-transmitted soundsignals. Sound source positioning techniques are the basis of othersound source processing techniques, and only if the position and thehorizontal angle of a sound source are determined by sound sourcepositioning techniques, the subsequent tasks such as beam forming, soundsource tracking, voice noise reduction and echo elimination can beconducted. If the position angle of the sound source positioned deviatesfrom the actual sound source position, the effectiveness of thesubsequent voice processing will be greatly reduced. Therefore, it is achallenge that a person skilled in the art faces to reduce the error ofsound source positioning and improve the accuracy of sound sourcepositioning.

SUMMARY

The present disclosure provides a method and device for sound sourcepositioning using a microphone array which can effectively reduce theerror of sound source positioning and improve the accuracy of soundsource positioning.

According to an aspect of the present disclosure, there is provided amethod for sound source positioning using a microphone array, whereinthe method comprises the steps of:

determining a horizontal axis that a microphone array rotates around asa reference axis;

acquiring an inclination angle between a plane in which the microphonearray is located when it is rotating and a horizontal plane in which thereference axis is located;

calculating, according to a sound emitted by a sound source that iscollected by the microphone array, to obtain a first sound sourceestimated value indicating a sound source position in athree-dimensional space; and according to the first sound sourceestimated value and the inclination angle, calculating out a secondsound source estimated value on a horizontal plane corresponding to thefirst sound source estimated value, and using the second sound sourceestimated value as the determined sound source position.

According to another aspect of the present disclosure, there is provideda device for sound source positioning using a microphone array, whereinthe device comprises:

an axis determining module, for determining a horizontal axis that amicrophone array rotates around as a reference axis;

an angle acquiring module, for acquiring an inclination angle between aplane in which the microphone array is located when it is rotating and ahorizontal plane in which the reference axis is located;

a first calculating module, for calculating, according to a soundemitted by a sound source that is collected by the microphone array, toobtain a first sound source estimated value indicating a sound sourceposition in a three-dimensional space; and

a second calculating module, for, according to the first sound sourceestimated value and the inclination angle, calculating out a secondsound source estimated value on a horizontal plane corresponding to thefirst sound source estimated value, and using the second sound sourceestimated value as the determined sound source position.

The advantageous effects of the present disclosure are as follows.According to the present disclosure, first, a first sound sourceestimated value indicating a sound source position in athree-dimensional space is obtained by calculating, according to a soundemitted by a sound source that is collected by the microphone array;then, in order to prevent the positioning error caused by the estimationof the sound source when the microphone array is inclining, aninclination angle between a plane in which the microphone array islocated when it is rotating and a horizontal plane in which thereference axis is located is acquired; and a second sound sourceestimated value on a horizontal plane corresponding to the first soundsource estimated value is calculated out according to the first soundsource estimated value and the inclination angle. Thereby, the demand ofsound source positioning when the microphone array is inclining issatisfied, while the positioning error of sound source in the inclinedstate of the microphone array is prevented, and the accuracy of soundsource positioning is improved. In addition, because the sound sourcecan be accurately positioned even when the microphone array isinclining, the design limitation of products having a microphone arrayin the prior art that the microphone array is required to behorizontally placed is broken through, which greatly improves the designflexibility and attractiveness level of product, provides more designoptions for the microphone array of product, and improves the marketcompetitiveness of product.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flow chart of a method for sound source positioning using amicrophone array in accordance with the present disclosure;

FIG. 2 is a schematic diagram of a positioning model of microphone arrayin the non-inclined state in accordance with the present disclosure;

FIG. 3 is a schematic diagram of a positioning model of microphone arrayin the inclined state in accordance with the present disclosure;

FIG. 4 is a schematic diagram of a pentahedron model that is constructedaccording to FIG. 3;

FIG. 5 is a schematic diagram of the principle of calculating the secondsound source estimated value in real time in accordance with the presentdisclosure;

FIG. 6 is a schematic diagram of a correspondence relation database inaccordance with the present disclosure;

FIG. 7 is a hardware structural diagram of a smart device in accordancewith the present disclosure; and

FIG. 8 is a functional block diagram of a device for sound sourcepositioning using a microphone array in accordance with the presentdisclosure.

DETAILED DESCRIPTION

The sound source positioning algorithms are implemented by a microphonearray consisting of a plurality of microphones. The most common form ofmicrophone array is that four (or more) microphones are evenlydistributed on a circle. Presently, the microphone arrays and most soundsource positioning techniques require that, in hardware design, themicrophone array is horizontally placed, because only when all of themicrophones in the microphone array are in the same horizontal plane,the error between the position obtained by the sound source positioningalgorithm and the actual sound source position can be reduced to aminimum.

The design concept of the present disclosure is as follows. Regardingthe problem of the prior art that the sound source positioningtechniques based on microphone arrays all require the microphones of themicrophone array to be located in the same horizontal plane, whichcannot satisfy the demands of some products, a technical solution forsound source positioning using a microphone array is proposed. Accordingto the technical solution of the present disclosure, first, a firstsound source estimated value in the three-dimensional space is obtainedby using the microphone array; then, according to an acquiredinclination angle between the plane in which the microphone array islocated when the it is inclining and the horizontal plane in which thereference axis is located, the mapping of the first sound sourceestimated value on the horizontal plane, namely, the second sound sourceposition, is calculated out, thereby satisfying the demands of theproducts in which the microphones of the microphone array cannot belocated in the same horizontal plane, reducing the error between thepositioned sound source position and the actual sound source positionwhen the microphone array is inclining, and improving the marketcompetitiveness of product.

In order to facilitate the understanding of the present disclosure, theprinciple of sound source positioning based on a microphone array isbriefly described herein.

Presently, there are mainly three methods for sound source positioningbased on a microphone array. The first method positions a sound sourceusing Time-Delay estimator technique and Delay Sum Beamformer technique.The Time-Delay estimator and Delay Sum Beamformer techniques haverelatively low positioning accuracy, so they have very limited use inthree-dimensional positioning and so on. The second method positions asound source using Maximum Likelihood Estimation generic algorithm andHigh Order Estimation generic algorithm. This method is very complicatedand needs a large amount of calculation, so it is usually used intheoretical research only. The third method positions a sound sourceusing near field sound source positioning technique. Specifically,first, a microphone array is formed by arranging a plurality ofmicrophones according to a certain topological structure, for example, 6omnidirectional microphones are uniformly distributed on a circle of adiameter of 40 centimeters to form a circular microphone array, to pickup the sound signal emitted by the sound source and all other voicesignals within the receiving range of the microphones; then the signalsreceived by each of the microphones are subject to a series ofprocessing such as analog-to-digital conversion, windowing and spectralsubtraction; finally, the incidence position angle of the sound sourceto the microphone array is calculated out, namely, the position anddirection of the sound source is judged.

The above microphone array-based sound source positioning techniques allrequire that all microphones of the microphone array be on the samehorizontal plane, to reduce the error between the sound sourcepositioning result and the actual value to a minimum. However, inpractice, some products cannot ensure that all microphones are in thesame horizontal plane. For example, in service robot products,typically, the microphone array is provided at the head of servicerobot. However, the head of service robot is often in a moving state,such as head lifting and head dropping, thus it cannot be ensured thatall microphones in the microphone array are in the same horizontalplane; in other words, the microphone array may incline. When themicrophone array rotates, the inclination angle between the plane inwhich the microphone array is located when it is rotating and thehorizontal plane in which the reference axis is located will increase,thus the error of the position angle of the positioned sound source willbe relatively larger.

The inventors of the present disclosure find that, none of theconventional sound source positioning techniques considers the situationof an inclining microphone array, and the positioning accuracy can beensured only when the microphone array is used in a completelyhorizontal state. The non-horizontal state of the microphone arrayaffects the measurement result of the microphone array to a certainextent. The measuring error varies with the inclination angle; when thesound source positioning result is 0 degree or 90 degrees, there is noinfluence (because they are perpendicular projection); when the soundsource positioning result is about 45 degrees, the influence isrelatively large, and the error (namely, the difference between thepositioned angle and the actual angle of the sound source) is as largeas about 20 degrees. Considering that the pick-up distance of themicrophone array is approximately 5 meters, the difference of thedistance to the object caused by the angle difference of 20 degrees isas large as about 1.5 meters, which is unacceptable.

In order to solve the above technical problems, the present disclosureprovides a method for sound source positioning using a microphone array.Referring to FIG. 1, the method comprises the following steps:

Step S101, determining a horizontal axis that a microphone array rotatesaround as a reference axis;

Step S103, acquiring an inclination angle between a plane in which themicrophone array is located when it is rotating and a horizontal planein which the reference axis is located;

Step S102, calculating, according to a sound emitted by a sound sourcethat is collected by the microphone array, to obtain a first soundsource estimated value indicating a sound source position in athree-dimensional space; and

Step S104, according to the first sound source estimated value and theinclination angle, calculating out a second sound source estimated valueon a horizontal plane, wherein the second sound source estimated valuecorresponds to the first sound source estimated value, and using thesecond sound source estimated value as the determined sound sourceposition.

The order of Step S102 and Step S103 is not fixed. Step S102 may precedeStep S103, and alternatively, Step S103 may precede Step S102, which isnot limited in the present disclosure. In practical applications, StepS101 and Step S103 need to be executed in advance only once, and whenthe sound source is positioned using a microphone array, Step S101 andStep S103 need not to be executed again, while Step S102 and Step S104must be executed every time.

It can be known from FIG. 1 that, the method for sound sourcepositioning using a microphone array of the present disclosure,calculates out the sound source position angle in the three-dimensionalspace according to the sound signal collected by the microphone array,then according to the acquired inclination angle of the microphonearray, calculates the sound source position angle within the horizontalplane corresponding to the position angle of the sound source in thethree-dimensional space after the microphone array is projected onto thehorizontal plane, thereby obtaining the horizontal sound source positionangle, which satisfies the practical demands, reduces the error betweenthe sound source positioning result and the actual sound source position(experiments confirm that, if the technical solution of the presentdisclosure is used, even when the microphone array seriously inclines,the positioning error of the sound source position angle is reduced from20 degrees to 3 degrees), and greatly improves the accuracy of soundsource positioning.

As calculating, according to a sound emitted by a sound source that iscollected by the microphone array to obtain a first sound sourceestimated value indicating a sound source position in athree-dimensional space, it can be realized by using the prior art (suchas the sound source positioning techniques based on steered beamformer,time difference of arrival or high resolution spectrum estimation). Thepresent embodiment, by referring to FIGS. 2 to 4, explains how tocalculate out a second sound source estimated value on a horizontalplane corresponding to the first sound source estimated value accordingto the first sound source estimated value and the inclination angle.

The embodiments of the present disclosure are described by taking thecommon circular microphone array as the example of the microphone array.As introduced above, the circular microphone array consists of aplurality of microphones that are evenly distributed on a circle. Inorder to better judge the inclined state of the microphone array, thepresent embodiment defines a horizontal axis which a microphone arrayrotates around as a reference axis, and the reference axis alwaysmaintains a completely horizontal state. When the microphone array isinclined, no matter how the inclining angle changes, its inclined statecan always be judged by the same horizontal reference basis in themicrophone array.

Referring to FIG. 2, the reference axis is the dotted line. FIG. 2 showsthat when the microphone array is not rotating, all microphones of themicrophone array (the microphones distributed on the circle in FIG. 2)are located in the same horizontal plane. In FIG. 2, 0 is the circlecenter of the circular microphone array, the radius OF₁ indicates the 0degree reference direction of sound source positioning, the radius OF₂indicates the direction of sound source, and the included angle Abetween the radius OF₁ and the radius OF₂ is the first sound sourceestimated value calculated out according to the sound signal collectedby the microphone array.

It can be seen from FIG. 2 that, when the microphone array is notrotating, the inclination angle between the plane in which themicrophone array is located and the horizontal plane in which thereference axis is located is 0 degree.

After the reference axis is determined, an inclination angle between aplane in which the microphone array is located when it is rotating and ahorizontal plane in which the reference axis is located is acquired. Inpractice, the microphone array will probably rotate. When the microphonearray is rotating, there will be a certain included angle, namely, aninclination angle, between the plane in which the microphone array islocated when it is rotating and the horizontal plane. The existing ofthe inclination angle results in that the first sound source estimatedvalue (namely, the sound source position angle) calculated out by themicrophone array and the actual sound source position have a relativelarge error, so it is required to be optimized to improve the accuracyof the sound source positioning.

The present embodiment provides two modes of acquiring the inclinationangle of the microphone array. The first mode is acquiring a constantangle value. In practical applications, the microphone arrays of someproducts are designed to keep a constant inclined state with a pitchangle. With respect to such a case, acquiring the inclination angle ofthe microphone array is acquiring a constant angle value, for example anangle B. The second mode is acquiring a changing inclination anglebetween a plane in which the microphone array is located when it isrotating and a horizontal plane in which the reference axis is locatedin real time by using a sensor. Such a mode is with respect to theproducts with changing inclination angles, for example, service robots.The head of service robot can move and the angle of head lifting may bedifferent, and correspondingly, the inclination angles of the microphonearray are different. The present embodiment collects the head movementof service robot in real time by using the sensor provided on the headof service robot, and thus determines the inclination angle of themicrophone array.

The sensor herein may be a magnetoelectric encoder or a Hall switch. Themeasuring principle of a Hall switch is similar to that of themagnetoelectric encoder. The magnetoelectric encoder is mounted onproducts (for example, service robots), and measures the changing angleof a magnetic material by the magnetic reluctance. The change of theangle of the magnetic material will cause the change of reluctance orvoltage. The amount of change is amplified by an amplifying circuit, andprocessed by a signal processing circuit to output a pulse signal or ananalog quantity signal, to complete the measuring. In some otherproducts, for example sound equipments, the inclination angle may bemeasured by a Hall switch.

After the first sound source estimated value and the inclination angleare obtained, a second sound source estimated value on a horizontalplane corresponding to the first sound source estimated value will becalculated out according to the first sound source estimated value andthe inclination angle.

When the microphone array consists of a plurality of microphones locatedin a same plane, a measuring graph is formed according to the plane inwhich the microphone array is located when it is rotating (or therotation axis passing through the center of the microphone array) andthe first sound source estimated value; then, a projection graph of themeasuring graph on the horizontal plane is obtained, and a projectionangle corresponding to the first sound source estimated value iscalculated by using a geometric position relation between the measuringgraph and the projection graph, a side length of the measuring graph,the first sound source estimated value and the inclination angle, toobtain the second sound source estimated value.

Referring to FIGS. 2 and 3, the step of calculating out a second soundsource estimated value on a horizontal plane corresponding to the firstsound source estimated value according to the first sound sourceestimated value and the inclination angle, particularly comprises thefollowing steps.

A measuring graph is formed according to the first sound sourceestimated value, a first rotation axis and a second rotation axis in thecircular microphone array that use a center (namely, the circle centerO) of the circular microphone array as a starting point. The firstrotation axis (the straight line on which the radius OF₁ is located)indicates the 0 degree reference direction of sound source positioning,the second rotation axis (the straight line on which the radius OF₂ islocated) indicates the positioned sound source direction, and the firstsound source estimated value (the angle A) is the included angle betweenthe first rotation axis and the second rotation axis.

As shown in FIG. 3, the measuring graph is a measuring triangle formedby a side OF₁ connecting the center (O) of the circular microphone arrayand an intersection point (F₁) between the first rotation axis and acircle of the circular microphone array, a side OF₂ connecting thecenter (O) of the circular microphone array and the intersection point(F₂) of the second rotation axis and the circle of the circularmicrophone array, and a side F₁F₂ connecting the two intersection points(F₁, F₂). Namely, the three sides of the measuring triangle are OF₁, OF₂and F₁F₂. A projection triangle OK₁K₂ is obtained by projecting themeasuring triangle OF₁F₂ onto the horizontal plane.

Referring to FIG. 3, a projection triangle can be obtained by projectingorthographically and downwardly the measuring triangle in the space ontothe horizontal plane. The side obtained by the projecting of the sideOF₁ is OK₁. Since the side OF₁ in the measuring triangle indicates the 0degree reference direction of sound source positioning, the side OK₁obtained by projecting also indicates the 0 degree reference directionof sound source positioning. The side obtained by the projecting of theside OF₂ is OK₂, and the side obtained by the projecting of the sideF₁F₂ is K₁K₂.

The angle B in FIG. 3 is the acquired inclination angle of themicrophone array as stated above, the value of B ranges from negative 90degrees to positive 90 degrees (“negative” and “positive” representdirections).

The projection angle on the horizontal plane corresponding to theinterior angle A of the measuring triangle is the interior angle C ofthe projection triangle. The sound source position that is mapped to thehorizontal plane by the sound source position in the space can beobtained by calculating out the value of the angle C.

After the measuring triangle and the projection triangle are obtained, apentahedron model can be formed by connecting the measuring triangle andthe projection triangle in the three-dimensional space with lines. Asshown in FIG. 4, the five planes of the pentahedron model OF₁F₂K₁K₂include: the measuring triangle OF₁F₂ located at an upper surface, theprojection triangle OK₁K₂ located at a lower bottom surface, and twolateral triangles (the first lateral triangle: OF₁K₁, and the secondlateral triangle: OF₂K₂) and a trapezoid (F₁F₂K₂K₁) that are obtained byconnecting vertexes of the measuring triangle and the projectiontriangle.

Since OF₁ and OF₂ are the radiuses of the circular microphone array andalready known, the angles A and B can be acquired. Accordingly, the sidelengths of the projection triangle can be obtained by geometriccalculation, and a value of the projection angle corresponding to thefirst sound source estimated value can be calculated out according tothe side lengths of the projection triangle, thereby the second soundsource estimated value can be obtained. In other words, the lengths ofthe sides OK₁, OK₂ and K₁K₂ can be calculated out using trigonometricfunction, then the angle C can be obtained using trigonometric function.It should be noted that, in the process of calculating the value of C,the radius R merely serves as an auxiliary parameter for calculating thesides of the triangle including the angle C, and the value of C is onlydependent on the angles A and B and is irrelevant to the radius R.

So far, the second sound source estimated value on the horizontal planecorresponding to the first sound source estimated value has beencalculated out according to the first sound source estimated value andthe inclination angle.

Based on the above calculating process and different demands inpractical applications, after obtaining the inclination angle B and thefirst sound source estimated value, the present disclosure provide twomodes to obtain the mapping angle C on the horizontal plane of the soundsource position.

The first mode is the real-time calculating mode. As discussed in theabove calculating process of the angle C, the second sound sourceestimated value (namely, the angle C) is calculated out in real timeaccording to the first sound source estimated value and the inclinationangle.

FIG. 5 is a schematic diagram of the principle of obtaining the value ofthe angle C using the real-time calculating mode in accordance with thepresent disclosure. As shown in FIG. 5, the acquired angles A and B areinput to the program for calculating the angle C executed by theprocessor as input parameters, namely, input parameters A and B, thenthe result is output, namely, the calculation result C is output. Theprogram of calculating the angle C is written in advance and correspondsto the above process of calculating the angle C.

The second mode is the table looking-up mode. FIG. 6 is a schematicdiagram of the correspondence relation database constructed in advancein accordance with the present disclosure. Referring to FIG. 6, itshows, for example, the correspondence relation between the first soundsource estimated value A and the projection angle C when the inclinationangle B is equal to 1°. It should be noted that, the values of theprojection angle C in the correspondence relation database shown in FIG.6 are calculated out respectively according to the above process ofcalculating the second sound source estimated value.

Particularly, a correspondence relation database recordingcorrespondence relations between the first sound source estimated valueand the second sound source estimated value is constructed according tothe first sound source estimated value and preset inclination angles orangle ranges, and according to the matching result between theinclination angle acquired in real time and the preset inclinationangles or angle ranges in the correspondence relation database, thesecond sound source estimated value corresponding to the first soundsource estimated value is determined at the matched preset inclinationangle or within the matched angle range. Namely, a correspondencerelation database between the first sound source estimated value A andthe second sound source estimated value C is constructed in advanceaccording to different inclination angles, and a plurality of lists arestored in the correspondence relation database.

When the mapping angle C is needed, the angle C can be obtained bylooking up the correspondence relation database according to the angle Band the first sound source estimated value A acquired in real time.

In addition, it should be noted that, FIG. 6 schematically illustratesthe correspondence relation database between the first sound sourceestimated value A and the second sound source estimated value C that isconstructed by using each of the inclination angles B as the primarykey. However, in practical applications, considering that the differencebetween the mapping angles corresponding to several inclination angleswith a small difference is relatively small, the second sound sourceestimated value C corresponding to the first sound source estimatedvalue A in an angle range may also be calculated and saved, namely, theangle range is used as the primary key. For example, an angle range [1,3] is defined to include the cases that the inclination angle is equalto 1 degree, 2 degrees and 3 degrees, the second sound source estimatedvalue C for one of the angles (for example 2 degrees) is calculated andsaved as the second sound source estimated value C for the angle range.Namely, the sound source estimated value of one of the angles serves asthe representative of the sound source estimated values in the anglerange. Thus, when the inclination angle collected in real time is 1degree and the first sound source estimated value is A, the angle range[1, 3] is matched with the 1 degree and determined as being matched, andthe second sound source estimated value C corresponding to the firstsound source estimated value A for the angle range [1, 3] is determinedas the mapping angle on the horizontal plane.

As discussed above, according to the present disclosure, with respect tothe inclining state of the microphone array, the inclined sound sourcepositioning result obtained by the conventional algorithm for soundsource positioning using a microphone array is mapped to the horizontaldirection by using horizontal mapping, thereby the accuracy of soundsource positioning is improved (experiments confirm that, thepositioning angle error of the sound source can be reduced from themaximum 20 degrees to 3 degrees). The present disclosure can greatlyimprove the hardware design of the products, particularly theflexibility of the appearance design. The microphone array in theproduct is no longer required to be horizontally placed and can beinclined to some extent, thereby the appearance can be more diverse andbeautiful, and the market competitiveness of the product is improved.

Corresponding to the above method, FIG. 7 shows a hardware structuraldiagram of the smart device in accordance with the present disclosure.Besides the processor and the memory shown in FIG. 7, according to thepractical functions of the smart device, the smart device may alsocomprise other hardware, which is not discussed here in detail. Thesmart device may be a smart robot, a smart sound equipment, a smarttelevision set and so on.

In FIG. 7, the memory stores machine executable instruction codes. Theprocessor communicates with the memory, and reads and executes theinstruction codes stored in the memory, to implement the operations ofsound source positioning using a microphone array that are disclosed inthe above examples of the present disclosure.

Herein, the memory may be any electronic, magnetic, optical or otherphysical storage devices, and may contain or store information, such asexecutable instructions, data and so on. For example, the machinereadable storage medium may be RAM (Random Access Memory), a volatilememory, a nonvolatile memory, a flash memory, a storage driver (such asa hard disk drive), a solid state disk, any type of memory discs (suchas an optical disk, DVD and so on), or similar storage media, or acombination thereof.

Referring to FIG. 8, the present disclosure further provides a devicefor sound source positioning using a microphone array, comprising:

an axis determining module 801, for determining a horizontal axis that amicrophone array rotates around as a reference axis;

an angle acquiring module 803, for acquiring an inclination anglebetween a plane in which the microphone array is located when it isrotating and a horizontal plane in which the reference axis is located;

a first calculating module 802, for calculating, according to a soundemitted by a sound source that is collected by the microphone array, toobtain a first sound source estimated value indicating a sound sourceposition in a three-dimensional space; and

a second calculating module 804, for, according to the first soundsource estimated value and the inclination angle, calculating out asecond sound source estimated value on a horizontal plane correspondingto the first sound source estimated value, and using the second soundsource estimated value as the determined sound source position.

In some embodiments of the present disclosure, the angle acquiringmodule 803 comprises: a constant angle acquiring module, for acquiring aconstant inclination angle between a plane in which the microphone arrayis located when it is rotating and a horizontal plane in which thereference axis is located; and a changing angle acquiring module, foracquiring in real time a changing inclination angle between a plane inwhich the microphone array is located when it is rotating and ahorizontal plane in which the reference axis is located by using asensor; and the sensor comprises a magnetoelectric encoder or a Hallswitch.

In some embodiments of the present disclosure, the second calculatingmodule 804 comprises a geometric relation constructing module, for, whenthe microphone array consists of a plurality of microphones located in asame plane, forming a measuring graph according to the plane in whichthe microphone array is located when it is rotating and the first soundsource estimated value; and obtaining a projection graph of themeasuring graph on the horizontal plane, and by using a geometricposition relation between the measuring graph and the projection graph,a side length of the measuring graph, the first sound source estimatedvalue and the inclination angle, calculating a projection anglecorresponding to the first sound source estimated value, to obtain thesecond sound source estimated value.

In some embodiments of the present disclosure, the microphone array is acircular microphone array consisting of a plurality of microphoneslocated in a same plane, and the geometric relation constructing moduleis particularly for forming a measuring graph according to the firstsound source estimated value, a first rotation axis and a secondrotation axis in the circular microphone array that use a center of thecircular microphone array as a starting point; wherein the firstrotation axis indicates a 0 degree reference direction for sound sourcepositioning, the second rotation axis indicates a direction of the soundsource, and the first sound source estimated value is an included anglebetween the first rotation axis and the second rotation axis; and

the measuring graph is a measuring triangle formed by a side connectingthe center of the circular microphone array and an intersection point ofthe first rotation axis and a circle of the circular microphone array, aside connecting the center of the circular microphone array and anintersection point of the second rotation axis and the circle of thecircular microphone array, and a side connecting the two intersectionpoints; and

projecting the measuring triangle onto the horizontal plane, to obtain aprojection triangle; connecting the measuring triangle and theprojection triangle with lines in the three-dimensional space, to form apentahedron model; wherein the five planes of the pentahedron modelinclude: the measuring triangle located at an upper surface, theprojection triangle located at a lower bottom surface, and two lateraltriangles and a trapezoid that are obtained by connecting vertexes ofthe measuring triangle and the projection triangle; and

obtaining side lengths of the projection triangle by geometriccalculation, and calculating out a value of the projection anglecorresponding to the first sound source estimated value according to theside lengths, thereby obtaining the second sound source estimated value.

In some embodiments of the present disclosure, the second calculatingmodule 804 comprises: a real-time calculating module, for, according tothe first sound source estimated value and the inclination angle,calculating in real time the second sound source estimated value; atable looking-up module, for, according to the first sound sourceestimated value and preset inclination angles or angle ranges,constructing a correspondence relation database that recordscorrespondence relations between the first sound source estimated valueand the second sound source estimated value, and according to a matchingresult between the inclination angle acquired in real time and thepreset inclination angles or angle ranges in the correspondence relationdatabase, determining the second sound source estimated valuecorresponding to the first sound source estimated value at the matchedpreset inclination angle or within the matched angle range.

Regarding the device embodiments, as they substantially correspond tothe method embodiments, the related parts can refer to the descriptionof the method embodiments. The description of the device embodimentsabove is merely illustrative, and a person skilled in the art may selectpart of or all of their modules according to the actual demands torealize the objects of the technical solution of the present embodiment.A person skilled in the art can understand and implement the technicalsolution without paying creative work.

It should be noted that, in the present disclosure, relation terms suchas “first” and “second” are merely used to distinguish one entity oroperation from another entity or operation, and they do not necessarilyrequire or imply that these entities or operations actually have such arelation or order. The terms “comprise”, “include” or any other variantsthereof are intended to cover nonexclusive inclusion, so that processes,methods, articles or devices that comprise a series of elements do notonly comprise those elements, but also comprise other elements that arenot explicitly listed, or further comprise elements that are intrinsicto such processes, methods, articles or devices. Where there is nofurther limitation, the statement “comprises a . . . ” does not excludethat there exist additional elements of the same kind in the processes,methods, articles or devices that comprise the element.

The above merely describes specific embodiments of the presentdisclosure. With the teaching of the present disclosure, a personskilled in the art can make other modifications or variations on thebasis of the above embodiments. A person skilled in the art shouldappreciate that, the specific description above is only for the purposeof better explaining the present disclosure, and the protection scope ofthe present disclosure should be subject to the protection scope of theclaims.

1. A method for sound source positioning using a microphone array,wherein the method comprises the steps of: determining a horizontal axisthat a microphone array rotates around as a reference axis; acquiring aninclination angle between a plane in which the microphone array islocated when it is rotating and a horizontal plane in which thereference axis is located; calculating, according to a sound emitted bya sound source that is collected by the microphone array, to obtain afirst sound source estimated value indicating a sound source position ina three-dimensional space; and according to the first sound sourceestimated value and the inclination angle, calculating out a secondsound source estimated value that corresponding to the first soundsource estimated value on a horizontal plane, and using the second soundsource estimated value as the determined sound source position.
 2. Themethod according to claim 1, wherein the step of acquiring aninclination angle between a plane in which the microphone array islocated when it is rotating and a horizontal plane in which thereference axis is located comprises the step of: acquiring a constantinclination angle between a plane in which the microphone array islocated when it is rotating and a horizontal plane in which thereference axis is located; or, acquiring in real time a changinginclination angle between a plane in which the microphone array islocated when it is rotating and a horizontal plane in which thereference axis is located by using a sensor, wherein the sensorcomprises a magnetoelectric encoder or a Hall switch.
 3. The methodaccording to claim 1, wherein the step of according to the first soundsource estimated value and the inclination angle, calculating out asecond sound source estimated value on a horizontal plane correspondingto the first sound source estimated value comprises the steps of: whenthe microphone array consists of a plurality of microphones located in asame plane, forming a measuring graph according to the plane in whichthe microphone array is located when it is rotating and the first soundsource estimated value; and obtaining a projection graph of themeasuring graph on the horizontal plane, and by using a geometricposition relation between the measuring graph and the projection graph,a side length of the measuring graph, the first sound source estimatedvalue and the inclination angle, calculating a projection anglecorresponding to the first sound source estimated value, to obtain thesecond sound source estimated value.
 4. The method according to claim 3,wherein the microphone array is a circular microphone array consistingof a plurality of microphones located in a same plane, and the step ofaccording to the first sound source estimated value and the inclinationangle, calculating out a second sound source estimated value on ahorizontal plane corresponding to the first sound source estimated valuecomprises the steps of: forming a measuring graph according to the firstsound source estimated value, a first rotation axis and a secondrotation axis in the circular microphone array that use a center of thecircular microphone array as a starting point; wherein the firstrotation axis indicates a 0 degree reference direction of sound sourcepositioning, the second rotation axis indicates a direction of the soundsource, and the first sound source estimated value is an included anglebetween the first rotation axis and the second rotation axis; andwherein the measuring graph is a measuring triangle formed by a sideconnecting the center of the circular microphone array and anintersection point of the first rotation axis and a circle of thecircular microphone array, a side connecting the center of the circularmicrophone array and an intersection point of the second rotation axisand the circle of the circular microphone array, and a side connectingthe two intersection points; projecting the measuring triangle onto thehorizontal plane, to obtain a projection triangle; connecting themeasuring triangle and the projection triangle with lines in thethree-dimensional space, to form a pentahedron model; wherein the fiveplanes of the pentahedron model include: the measuring triangle locatedat an upper surface, the projection triangle located at a lower bottomsurface, and two lateral triangles and a trapezoid that are obtained byconnecting vertexes of the measuring triangle and the projectiontriangle; and obtaining side lengths of the projection triangle bygeometric calculation, and calculating out a value of the projectionangle corresponding to the first sound source estimated value accordingto the side lengths, thereby obtaining the second sound source estimatedvalue.
 5. The method according to claim 1, wherein the step of accordingto the first sound source estimated value and the inclination angle,calculating out a second sound source estimated value on a horizontalplane corresponding to the first sound source estimated value comprisesthe steps of: according to the first sound source estimated value andthe inclination angle, calculating in real time the second sound sourceestimated value; or, according to the first sound source estimated valueand preset inclination angles or angle ranges, constructing acorrespondence relation database that records correspondence relationsbetween the first sound source estimated value and the second soundsource estimated value, and according to a matching result between theinclination angle acquired in real time and the preset inclinationangles or angle ranges in the correspondence relation database,determining the second sound source estimated value corresponding to thefirst sound source estimated value at the matched preset inclinationangle or within the matched angle range.
 6. A device for sound sourcepositioning using a microphone array, wherein the device comprises: anaxis determining module, for determining a horizontal axis that amicrophone array rotates around as a reference axis; an angle acquiringmodule, for acquiring an inclination angle between a plane in which themicrophone array is located when it is rotating and a horizontal planein which the reference axis is located; a first calculating module, forcalculating, according to a sound emitted by a sound source that iscollected by the microphone array, to obtain a first sound sourceestimated value indicating a sound source position in athree-dimensional space; and a second calculating module, for, accordingto the first sound source estimated value and the inclination angle,calculating out a second sound source estimated value on a horizontalplane corresponding to the first sound source estimated value, and usingthe second sound source estimated value as the determined sound sourceposition.
 7. The device according to claim 6, wherein the angleacquiring module comprises: a constant angle acquiring module, foracquiring a constant inclination angle between a plane in which themicrophone array is located when it is rotating and a horizontal planein which the reference axis is located; and a changing angle acquiringmodule, for acquiring in real time a changing inclination angle betweena plane in which the microphone array is located when it is rotating anda horizontal plane in which the reference axis is located by using asensor, wherein the sensor comprises a magnetoelectric encoder or a Hallswitch.
 8. The device according to claim 6, wherein the secondcalculating module comprises a geometric relation constructing module,for, when the microphone array consists of a plurality of microphoneslocated in a same plane, forming a measuring graph according to theplane in which the microphone array is located when it is rotating andthe first sound source estimated value; and obtaining a projection graphof the measuring graph on the horizontal plane, and by using a geometricposition relation between the measuring graph and the projection graph,a side length of the measuring graph, the first sound source estimatedvalue and the inclination angle, calculating a projection anglecorresponding to the first sound source estimated value, to obtain thesecond sound source estimated value.
 9. The device according to claim 8,wherein the microphone array is a circular microphone array consistingof a plurality of microphones located in a same plane, and the geometricrelation constructing module is particularly for forming a measuringgraph according to the first sound source estimated value, a firstrotation axis and a second rotation axis in the circular microphonearray that use a center of the circular microphone array as a startingpoint; wherein the first rotation axis indicates a reference 0 degreereference direction for sound source positioning, the second rotationaxis indicates a direction of the sound source, and the first soundsource estimated value is an included angle between the first rotationaxis and the second rotation axis; and wherein the measuring graph is ameasuring triangle that is formed by a side connecting the center of thecircular microphone array and an intersection point of the firstrotation axis and a circle of the circular microphone array, a sideconnecting the center of the circular microphone array and anintersection point of the second rotation axis and the circle of thecircular microphone array, and a side connecting the two intersectionpoints; and projecting the measuring triangle onto the horizontal plane,to obtain a projection triangle; connecting the measuring triangle andthe projection triangle with lines in the three-dimensional space, toform a pentahedron model; wherein the five planes of the pentahedronmodel include: the measuring triangle located at an upper surface, theprojection triangle located at a lower bottom surface, and two lateraltriangles and a trapezoid that are obtained by connecting vertexes ofthe measuring triangle and the projection triangle; and obtaining sidelengths of the projection triangle by geometric calculation, andcalculating out a value of the projection angle corresponding to thefirst sound source estimated value according to the side lengths,thereby obtaining the second sound source estimated value.
 10. Thedevice according to claim 6, wherein the second calculating modulecomprises: a real-time calculating module, for, according to the firstsound source estimated value and the inclination angle, calculating inreal time the second sound source estimated value; or, a tablelooking-up module, for, according to the first sound source estimatedvalue and preset inclination angles or angle ranges, constructing acorrespondence relation database that records correspondence relationsbetween the first sound source estimated value and the second soundsource estimated value, and according to a matching result between theinclination angle acquired in real time and the preset inclinationangles or angle ranges in the correspondence relation database,determining the second sound source estimated value corresponding to thefirst sound source estimated value at the matched preset inclinationangle or within the matched angle range.
 11. A smart device, wherein thesmart device comprises a processor and a memory, the memory stores amachine executable instruction code, and the processor communicates withthe memory, and reads and executes the instruction code stored in thememory, to realize a method for sound source positioning using amicrophone array, wherein the method comprises the steps of: determininga horizontal axis that a microphone array rotates around as a referenceaxis; acquiring an inclination angle between a plane in which themicrophone array is located when it is rotating and a horizontal planein which the reference axis is located; calculating, according to asound emitted by a sound source that is collected by the microphonearray, to obtain a first sound source estimated value indicating a soundsource position in a three-dimensional space; and according to the firstsound source estimated value and the inclination angle, calculating outa second sound source estimated value on a horizontal planecorresponding to the first sound source estimated value, and using thesecond sound source estimated value as the determined sound sourceposition.
 12. The smart device according to claim 11, wherein the stepof acquiring an inclination angle between a plane in which themicrophone array is located when it is rotating and a horizontal planein which the reference axis is located comprises the step of: acquiringa constant inclination angle between a plane in which the microphonearray is located when it is rotating and a horizontal plane in which thereference axis is located; or, acquiring in real time a changinginclination angle between a plane in which the microphone array islocated when it is rotating and a horizontal plane in which thereference axis is located by using a sensor, wherein the sensorcomprises a magnetoelectric encoder or a Hall switch.
 13. The smartdevice according to claim 11, wherein the step of according to the firstsound source estimated value and the inclination angle, calculating outa second sound source estimated value on a horizontal planecorresponding to the first sound source estimated value comprises thesteps of: when the microphone array consists of a plurality ofmicrophones located in a same plane, forming a measuring graph accordingto the plane in which the microphone array is located when it isrotating and the first sound source estimated value; and obtaining aprojection graph of the measuring graph on the horizontal plane, and byusing a geometric position relation between the measuring graph and theprojection graph, a side length of the measuring graph, the first soundsource estimated value and the inclination angle, calculating aprojection angle corresponding to the first sound source estimatedvalue, to obtain the second sound source estimated value.
 14. The smartdevice according to claim 13, wherein the microphone array is a circularmicrophone array consisting of a plurality of microphones located in asame plane, and the step of according to the first sound sourceestimated value and the inclination angle, calculating out a secondsound source estimated value on a horizontal plane corresponding to thefirst sound source estimated value comprises the steps of: forming ameasuring graph according to the first sound source estimated value, afirst rotation axis and a second rotation axis in the circularmicrophone array that use a center of the circular microphone array as astarting point; wherein the first rotation axis indicates a 0 degreereference direction of sound source positioning, the second rotationaxis indicates a direction of the sound source, and the first soundsource estimated value is an included angle between the first rotationaxis and the second rotation axis; and wherein the measuring graph is ameasuring triangle formed by a side connecting the center of thecircular microphone array and an intersection point of the firstrotation axis and a circle of the circular microphone array, a sideconnecting the center of the circular microphone array and anintersection point of the second rotation axis and the circle of thecircular microphone array, and a side connecting the two intersectionpoints; projecting the measuring triangle onto the horizontal plane, toobtain a projection triangle; connecting the measuring triangle and theprojection triangle with lines in the three-dimensional space, to form apentahedron model; wherein the five planes of the pentahedron modelinclude: the measuring triangle located at an upper surface, theprojection triangle located at a lower bottom surface, and two lateraltriangles and a trapezoid that are obtained by connecting vertexes ofthe measuring triangle and the projection triangle; and obtaining sidelengths of the projection triangle by geometric calculation, andcalculating out a value of the projection angle corresponding to thefirst sound source estimated value according to the side lengths,thereby obtaining the second sound source estimated value.
 15. The smartdevice according to claim 11, wherein the step of according to the firstsound source estimated value and the inclination angle, calculating outa second sound source estimated value on a horizontal planecorresponding to the first sound source estimated value comprises thesteps of: according to the first sound source estimated value and theinclination angle, calculating in real time the second sound sourceestimated value; or, according to the first sound source estimated valueand preset inclination angles or angle ranges, constructing acorrespondence relation database that records correspondence relationsbetween the first sound source estimated value and the second soundsource estimated value, and according to a matching result between theinclination angle acquired in real time and the preset inclinationangles or angle ranges in the correspondence relation database,determining the second sound source estimated value corresponding to thefirst sound source estimated value at the matched preset inclinationangle or within the matched angle range.